A BURNLEY shop is one of the first businesses in East Lancashire to use an ultrasonic alarm that can only be heard by youngsters, in the fight against anti-social behaviour.

The Spar, Brunshaw Road, Pike Hill, is trialling the use of the "mosquito alarm" to deter youths from hanging around the shop entrance and intimidating customers.

The mosquito alarm is so called because of the high-pitched electronic pulse that it emits.

Most people under 20 can hear the whine, but hardly anybody over 30 is able to, because youngsters' hearing is more acute.

Spar has introduced the £500 system at the Burnley branch following successful pilots elsewhere.

Sales at the Spar branch in Barry, South Wales, increased after the first alarm was fitted in 2005, and incidents of shoplifting fell as youths were driven off by the irritating noise.

A spokesperson for the company said that the device had been fitted in Burnley to make customers feel more comfortable, but also for the benefit of the local community as it encourages youths to stop hanging around the streets.

John Hodgson, from James Hall Distributors, which owns the Pike Hill branch, said: "The store has installed a mosquito' device to deter local youths from congregating outside the store after complaints from customers.

"The decision was taken at this particular store following consultation with the police and there are no further plans to provide other Spar stores in the area with these devices."

Originally developed by Welsh company Compound Security, the "mosquito" has been welcomed by traders and police nationwide.

Railway companies have also used the device to discourage youths from spraying graffiti.